A particular problem attends electroylsis cells for swimming pools. Such cells require an integral transformer and rectifier in order to provide the low voltage DC for electrolysing the dilute salt solutions of the pool, whereby chlorine is liberated at the cell anode. The transformer operates at mains voltage and must therefore be shielded from the ingress of water.
The design of a shield for the transformer in particular poses problems. Firstly, the shield must be proof against rain, hose-directed water and the general spray of a swimming pool location. Secondly, the shield must be proof against the metal-corroding influence of brine in the pool. Thirdly, the shield must allow adequate cooling if the transformer is to have a commercially acceptable operating life. Fourthly, the shield must permit the dissipation of extra heat, such as solar heat.
One known salt water chlorinator relies upon an enamelled steel box to enclose the transformer, but the more waterproof the box, the higher the operating temperature tends to rise.